#pragma once

#include <iostream>
#include <string>
#include <cerrno>
#include <cstring>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <functional>
#include "Log.hpp"
#include "InetAddr.hpp"

enum
{
    SOCKET_ERROR = 1,
    BIND_ERROR,
    USAGE_ERROR
};

const static int defaultfd = -1;

using func_t = std::function<std::string(const std::string&, bool &ok)>;

class UdpServer
{
public:
    UdpServer(uint16_t port, func_t func)
        : _port(port)
        , _sockfd(defaultfd)
        , _isrunning(false)
        , _func(func)
    {
    }
    void InitServer()
    {
        // 1. 创建udp  socket 套接字 ---> 必要
        _sockfd = socket(AF_INET, SOCK_DGRAM, 0);   // struct sockaddr_in 系统提供的数据类型。local是变量，用户栈上开辟空间。int a = 100; a = 20;
        if (_sockfd < 0)
        {
            LOG(FATAL, "socket error , %s , %d", strerror(errno), errno);
            exit(SOCKET_ERROR);
        }
        LOG(INFO, "socket create success,sockfd: %d", _sockfd);

        // 2. 填充sockaddr_in 结构
        struct sockaddr_in local;
        bzero(&local, sizeof(local));
        local.sin_family = AF_INET;
        local.sin_port = htons(_port);  // port要经过网络传输给对面，先到网络，_port：主机序列-> 主机序列，转成网络序列
        // a. 字符串风格的点分十进制的IP地址转成 4 字节IP
        // b. 主机序列，转成网络序列
        // in_addr_t inet_addr(const char *cp) -> 同时完成 a & b
        // local.sin_addr.s_addr = inet_addr(_ip.c_str()); // "192.168.3.1" -> 字符串风格的点分十进制的IP地址 -> 4字节IP
        local.sin_addr.s_addr = INADDR_ANY;

        // 2.1 bind sockfd和网络信息(IP(?) + Port)
        int n = bind(_sockfd, (struct sockaddr *)&local, sizeof(local));
        if (n < 0)
        {
            LOG(FATAL, "bind error , %s , %d", strerror(errno), errno);
            exit(BIND_ERROR);
        }
        LOG(INFO,"socket bind success");
    }
    void Start()
    {
        // 服务器一直运行 
        // UDP 面向数据报协议
        _isrunning = true;
        while(true)
        {
            char request[1024];
            struct sockaddr_in peer;
            socklen_t len = sizeof(peer);

            ssize_t n = recvfrom(_sockfd, request, sizeof(request) - 1, 0, (struct sockaddr *)&peer, &len);
            if(n > 0)
            {
                request[n] = 0;
                InetAddr addr(peer);
                LOG(DEBUG,"get message from [%s:%d]: %s",addr.Ip().c_str(), addr.Port(), request);
                bool ok;
                std::string response = _func(request, ok); // 将请求回调出去，在外部进行处理

                sendto(_sockfd, response.c_str(), response.size(), 0, (struct sockaddr *)&peer, len);
            }
        }
        _isrunning = false;        
    }
    ~UdpServer()
    {
    }

private:
    int _sockfd;
    uint16_t _port; // 端口
    bool _isrunning;
    func_t _func;
};